Apparatus for treating the physiological electric conduction of the heart

ABSTRACT

A new pacemaker apparatus for treating the physiological electric conduction of the heart that includes a conduction abnormality in a ventricle. The pacemaker includes a pulse generator and a pacing electrode located in the heart, the pulse generator providing pacing signals to the pacing electrode. The pacemaker further includes a signal generation circuit that generates electrical signals from heart-related feedback signals that indicate that the pacing electrode is delivering the pacing signals in a region at or near the His bundle of the heart. The combination of the pulse generator and the signal generation circuit indicates that the pacing electrode is delivering the pacing signals in the region, at or near the His bundle of the heart, to electrically bypass the conduction abnormality of the heart in the ventricle.

RELATED PATENT DOCUMENTS

This patent document a continuation under 35 U.S.C. §120 of U.S. patentapplication Ser. No. 12/249,479, filed on Oct. 10, 2008, now issued asU.S. Pat. No. 8,437,848, which is a continuation under 35 U.S.C. §120 ofU.S. patent application Ser. No. 11/300,242 filed on Dec. 13, 2005, nowissued as U.S. Pat. No. 8,346,358, which claims foreign priority toArgentina Patent Application No. 20040104782 filed on Dec. 20, 2004 byinventors Daniel Felipe Ortega and Alberto German Giniger and entitled“A NEW PACEMAKER WHICH REESTABLISHES OR KEEPS THE PHYSIOLOGICAL ELECTRICCONDUCTION OF THE HEART AND A METHOD OF APPLICATION.”

BACKGROUND OF THE INVENTION

The present invention relates to a new pacemaker which reestablishes orkeeps the physiological electric synchrony of the heart and a method ofapplication in the right ventricular septum, being possible to use, inorder to facilitate the implantation and to avoid the connection anddisconnection, a sheath to check a proper place and then screw thecatheter in said place.

This method together with the pacemaker are responsible for thereestablishment and preservation of the physiological electric synchronyof the heart and is herein referred to as “EB (Electric Bypass)” due tothe obtention of an alternative electric circuit and to the creation ofthe virtual electrode.

With the pacemaker of my invention and its method of application, aseptal ventricular stimulation system with a high performance electricaland contractile synchrony is produced, thus significantly changing theimplantation of a definitive pacemaker, making them more physiological.In the examples where my invention was applied, several patients withQRS narrowing were tested as well as those suffering disorders in the AVatrio-ventricular and intraventricular impulse conduction. The resultsshow the QRS narrowing phenomena and the orientation of thedepolarization with similar vectors compared to those of adepolarization by the His-Purkinje system.

A pacemaker is an electronic apparatus that produces electric impulses,intended to stimulate the cardiac muscle. The number of impulsesproduced per minute is called frequency. The mechanism is fed fromelectric power from batteries. These electric impulses are conducted tothe heart by means of a cable (or electrode), so that the pacemakeritself (or pulse generator) is placed at a quite shallow surfaceunderneath the skin, while the electrode is placed much more deeplyinside the organism, up to the heart.

The first pacemakers, asynchronous, were only blind instruments thatcontinuously produced 70 electric impulses per minute, carrying them upto the heart by means of an electrode. The electronic circuit consistedof a few diodes, transistors, resistors and a capacitor. One or morebatteries provided the necessary power to feed the circuit and stimulatethe heart. These pacemakers complied very well with their role when thepatient's own rhythm was absolutely absent. However when the failure inthe rhythm was just intermittent, the pacemaker slightly interfered withthe normal rhythm, at the moments when it was reestablished.

Afterwards, the more intelligent pacemakers came out, Pacemakers ondemand, that stopped functioning when the cardiac rhythm wasreestablished. This supposed the introduction of new circuits, capableof detecting the electronic activity of the heart and new pacemakerswere called “on demand” since they just started working when they werenecessary.

Pacemakers on demand may be implanted in the atrium, in order to treatfailures in the sinus node; or in the ventricle so as to treat the heartblock.

An important advancement in the development of programmable pacemakerswas to make them more versatile. The first ones only worked under afrequency set in factory, with fixed pulse energy and were able todetect certain level of cardiac electric activity also fixed.

It may be interesting to be able to change the stimulation frequency atcertain moments, adjusting it to the organic needs. In other cases, adecrease in the pulse energy may be advantageous to save power andextend the duration of the pacemaker, or on the contrary, increase it ifthe muscle became resistant. In some patients, it would be useful to getthe pacemaker to have higher o lower capacity for detecting electricimpulses, in order to eliminate the influence of abnormal rhythms, orexternal interferences. All of the above-mentioned options becamepossible with the introduction of the Programmable Pacemaker.

Currently, different kinds of these pacemakers are available, whichallow the adjustment of their function to different states of healthy orsick organism without causing any discomfort to the patient.

Programmable pacemakers are insensitive to the needs of the organism andtheir functioning is to be changed from the outside, so that theiradaptability is relative. There are other kinds of pacemakers which aremore physiological, that is to say, more capable of meeting the organicneeds at every moment, with its continuos fluctuation. In cases wherethe formation of the cardiac stimulus in the atria is maintained, andthe problem lies on the conduction block between the atria and theventricles, a kind of pacemaker which senses atrial activity and thenstimulates the ventricles can be introduced. These are the “atrialtriggered” pacemakers, which constitute a practical reality, once theproblems of implanting two catheters, one in the auricle and the otherin the ventricle, are solved. In these pacemakers, as the variations inthe atrial rhythm depend on organic needs variations, the pacemaker isled by the body needs

Currently, for cases where it is not possible to use atrial guidance,pacemakers have been developed that are capable of sensing otherparameters in the body activity, changing automatically their frequency(self-programming frequency pacemakers). Some pacemakers catchvibrations of the body during movement; others detect breathing activityand accelerate frequency of the heart in combination with the frequencyof breathing; others detect fine vibrations in the cardiac electricactivity caused by exercise and others being at the stage of design orproject respond to the exhaustion of oxygen in blood, to changes in bodytemperature, or even to many of these causes.

First pacemakers were big and short-lasting. They weighted one hundredgrams, had a diameter of 7-8 cm, and 2-3 cm of thickness, wrapped withsilicone rubber toughly applied. They were fed by mercury-zinc batteriesthat could last no more than 2-3 years. Electrodes broke frequentlybecause of the phenomenon called “fatigue of materials”.

Nowadays, size has been reduced by a quarter or a fifth, weight has beenreduced to less than a third, duration reaches 5-10 years according tothe designs, and electrodes are made of a certain design and materialthat practically prevent their breaking and allow energy savings.

At present, we have smaller pacemakers, more powerful, long lasting,more versatile and more comfortable for the patient.

Traditional ventricular stimulation in the apex of the right ventricle(RV) is well known in the art, which through several years of use, ithas shown an important reliance as regards permanence of the catheter inthe correct place, control of the cardiac frequency and facility for itsimplantation. FIG. 9 illustrates a chart that shows right ventricularstimulation, “Standard Bipolar Stimulation on apex of RV”. However, dayafter day it is proven that regardless of the fact that it keepsatrio-ventricular synchrony through stimulation of both chambers,results are far away from causing a real physiological synchrony. Rightventricular stimulation on the apex of RV generates a pattern ofelectric activation, asynchronous in itself and therefore asynchronousleft ventricular contraction.

On the other hand, stimulation in the apex of the RV can lead tonon-homogenous left ventricular contraction, myofibril erradication, anddisorders of myocardic perfussion. This generates an increase in themorbidity and mortality of these patients, therefore leading fromseveral years ago to look for other places of unique and simultaneousstimulation in order to improve electric and hemodynamic parameters ofpermanent stimulation.

As it can be seen novelty in pacemakers was only slightly related to theplace of application of electrodes. In the new pacemaker of myinvention, it can be seen as an advantage, apart from those described inthe previous art, when applied on patients with pacemaker indicationwith preserved interventricular contraction, it prevents fromdeleterious effects of the traditional pacemaker over the ventricularfunction.

Also there are some advantages for patients with disorders inintraventricular impulse conduction and allows the re-establishment ofthe normal intraventricular activation sequency.

Other advantage is that in patients who suffered from heart failure withblockage in its left branch, allows me to apply well-known advantages ofre-synchronization through using only one catheter, so as to obtain theelectric alternative circuit procedure that we herewith call EB ElectricBypass.

As already known, traditional ventricular stimulation in the apex ofright ventricle (RV) has shown along the years, great trust as regardsits permanence, control of the cardiac frequency and ease for itsintroduction. However, day by day it has been proved that regardless thefact that it keeps atrio-ventricular synchrony through stimulation ofboth chambers, results are far away of causing a real phyisologicalsynchrony. Right ventricular stimulation on apex of RV generates apattern of electric activity, asynchronic in itself and thereforecontraction and asynchronic left ventricular contraction.

On the other hand, stimulation in the apex of the RV can lead tonon-homogenous left ventricular contraction, myofibril erradication, anddisorders of myocardic perfussion. These disorders cause an increase inthe morbidity and mortality of these patients, therefore leading fromseveral years ago to look for other places of unique and simultaneousstimulation in order to improve electric and hemodynamic parameters ofconstant stimulation.

In the illustrative examples attached to the present invention itssignificant usefulness is shown, in presence of left ventriculardysfunction with dual-chamber (AV) pacing, resynchronizing its activitywith only one catheter in RV septum, without the need of specialelectrophysiologist training, as seen in FIG. 9. Therefore the potentialoutbreak in the use of the pacemaker of the invention for constantstimulation is shown.

SUMMARY OF THE INVENTION

According to an embodiment of the present invention, a pacemakerapparatus is disclosed for use in a heart treatment environment in whichthe heart includes a conduction abnormality in a ventricle. Suchpacemaker apparatus includes a pacing electrode located in the heart, apulse generator that provides pacing signals to the pacing electrode inthe heart, and a signal generation circuit that generates electricalsignals from heart-related feedback signals that indicate that thepacing electrode is delivering the pacing signals in a region at or nearthe His bundle of the heart, wherein the combination of the pulsegenerator and the signal generation circuit indicates that the pacingelectrode is delivering the pacing signals in the region, at or near theHis bundle of the heart, to electrically bypass the conductionabnormality of the heart in the ventricle.

According to another embodiment of the present invention, a pacemakerapparatus is disclosed for use in a heart treatment environment in whichthe heart includes a conduction abnormality, the pacemaker apparatusincluding a pulse generator to provide pacing signals, at least onepacing electrode to carry the pacing signals between the pulse generatorand a ventricle of the heart, a catheter to deliver the pacing electrodeto the heart, and a guide sheath to guide the catheter and the pacingelectrode to a target pacing region at or near the His bundle of theheart, the guide sheath including at least one sheath electrode todeliver pacing signals to the heart.

According to another embodiment of the present invention, a pacemaker isdisclosed which reestablishes or keeps the physiological electricconduction of the heart and a method of application.

Other aspects of the invention are described in the discussion ofexamples that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows as an example of first case patient with anelectrophysiology recording showing a narrow QRS and a septal electricalbypass stimulation according to the present invention showing just aslight widening of the QRS (first half of the figure) with a conductionsequence similar to the one of the basal QRS. FIG. 1.

FIG. 2 is an electrophysiology recording of to a patient with a completeleft branch block and ventricular malfunction, the time of basalconduction from the beginning of the QRS to the deflection correspondingto the left ventricle through the distal electrode of a multipolarcatheter placed in the coronary sinus (164 msec).

FIG. 3 is an electrophysiology recording showing the reduction of suchtime of conduction for the patient of FIG. 2 when electrical bypassstimulation according to the present invention is stimulated in septum(90 msec).

FIG. 4 is an electrophysiology recording for the patient of FIG. 2 wherethe electrical bypass stimulation according to the present invention isin apex of the right ventricle and keeps a conduction time to the leftventricle (169 msec) (similar to the basal time), when keeping thecomplete left branch block.

FIG. 5 shows an ECG of a patient with sinusal rhythm and complete blockof the left branch, as the septal stimulation of high penetrationelectrical bypass stimulation according to the present invention“normalizes” the QRS, narrowing it. A proof of the “physiologicalchange” in the sequence of intraventricular conduction is also thepresence of the QRS narrowing, changes of the ventricularrepolarization, with negative T waves in the precordial leads, probablysecondary to “electrotonic memory”.

FIG. 6 is an ECG showing stimulation on apex of the right ventricle andfollows a similar behavior to the presence of complete left branch blockin the basal ECG and with case septal electrical bypass stimulationnarrows the QRS and generates the same changes on ventricularrepolarization.

FIG. 7 is an ECG showing on its left side how EB pacing captures theventricles with narrow QRS and normal depolarization-repolarizationpattern.

FIG. 8 is an ECG in a patient with left bundle branch block and wherethe fusion with extrasystoles coming from the right ventricle areexpressed as a significantly narrow QRS.

FIG. 9 is a cross section view of the heart with the electrode in SeptalEB1 stimulation.

FIG. 10 is a cross section view of the heart with the electrode inseptum RV stimulation.

FIG. 11 is a cross section view of the heart with septal EB1stimulation.

FIG. 12 is a cross section view of the heart with septal EB2stimulation.

DETAILED DESCRIPTION OF THE INVENTION

This new pacemaker is intended to render a stimulation of a high septalpenetration as already mentioned called herein “EB (Electric Bypass)” aspreviously mentioned, and which involves a real approach to thepermanent physiological pacing.

Apart from the method for application to facilitate the implantation andto avoid the connection and disconnection of the catheter, a deflectablesheath can be used with an electrode on its edge which allows astimulation to verify the proper place and then screw the catheter insaid place. This sheath is removed after finding the proper place forstimulation and is eventually disposable.

Likewise, in the present invention apart from the new pacemaker and itsmethod of application, a new right septal stimulation is described,which allows the generation of a wave front with simultaneousventricular depolarization and QRS narrowing either in patients withnormal QRS or in those with conduction disorders.

The normal conduction throughout the His-Purkinje system produces a fastsynchronic sequential depolarization of the myocardial fibers causing amore efficient ventricular contraction. It is already known that thebest place for pacing to prevent the ventricular dissynchrony keepingits normal activity while applying the catheter is the His bundle.

Several methods have been developed to reach the His Bundle by septalstimulation. However there were several troubles in its implementation,requiring special treatment for finding the catheter, with variableresults.

Together with the pacing system including the new pacemaker and itsmethod of application, by septal implementation the wavefrontpenetration to the Hisian mainstream is obtained. The result is a narrowQRS, similar to the one in the normal conduction and with an almostnormal hemodynamic efficiency.

With reference to FIGS. 11 and 12, a heart H is shown in cross-sectionshowing a right ventricle RV and a left ventricle LV divided by a septumS. A catheter is provided in the right ventricle RV with a distalelectrode 12 secured to the septum and a proximal electrode 14 in theright ventricle. The right-hand side of the figures show the catheter 10enlarged and energized by a pacemaker 1 to create two monopolarpulsewaves between the electrodes 12, 14 and the pacemaker 1. FIGS. 11and 12 differ only in the figures show two different phases for thepulsewaves.

The present pacemaker 1 is a pulse generator, single-chambered ordual-chambered, with conventional features: it has a ventricular outputincluding at least two superimposed monopolar pulsewaves of reversedpolarity between each other, with programmable configuration, in respectto a neutral which can be the pacemaker's metallic box or a thirdelectrode in the case of a tripolar catheter. The distal electrode 12 ofthis catheter 10 is fixed in the right ventricular RV septum S for theventricular stimulation, thus producing an electrical alternativecircuit or Electrical Bypass (EB) of the bundle block, being anon-conventional cardiac stimulation application place, so we are in thepresence of a new use by the creation of a virtual electrode for thephysiological electric synchrony of the heart. Two charts showing twodifferent options can be seen in FIGS. 9 and 10. One of them is entitled“Septal Stimulation EB1” and the other is entitled “Septal StimulationEB2”. In FIG. 9 (Septal Stimulation EB1), the distal electrode 14 issecured to the apex of the right ventricle RV. In FIG. 10, the distalelectrode is secured to the septum S.

In each of FIGS. 9 and 10, the heart H is shown divided into regions1-5. In FIG. 9, Region 1 is the left ventricle postero basal side.Region 2 is the left ventricle lateral. Region 3 is the right ventriclebasal side. Region 4 is the apex right ventricle septum apical andRegion 5 is the apex left ventricle. In FIG. 10, Region 1 is the leftventricle postero basal side. Region 2 is the left ventricle lateral.Region 3 is the apex left ventricle. Region 4 is the apex rightventricle septum apical and Region 5 is the right ventricle lateral.

In the method of application and the way to facilitate the implantationand to avoid the connection and disconnection of the catheter, adeflectable sheath with an electrode in its edge can be used, whichallows stimulation, in order to check the proper place and then screwthe catheter in said place. This sheath is removed after finding theproper stimulation place and is eventually disposable.

According to one example, a new pacemaker and its method of applicationincludes the following items:

a pulse generator, single-chambered or dual-chambered, with conventionalfeatures: it has a ventricular output including at least twosuperimposed monopolar pulsewaves of reversed polarity between eachother, with programmable configuration, in respect to a neutral whichcan be the pacemaker's metallic box or a third electrode in the case ofa tripolar catheter;

a conventional active-fixation ventricular catheter;

a deflectable sheath with an electrode on its distal tip;

a stimulation place in the right interventricular septum;

the right interventricular septum stimulation place, is the one whichallows a greater interventricular synchrony making the left stimulationeasier and the application of the electric alternative circuit principleor Electrical Bypass that reestablishes the physiological conduction ofthe heart when damaged.

Apart from the new pacemaker and its method of application with thedeflectable sheath with an electrode on its edge, the present inventiondescribes a new technique for the right septal stimulation which allowsthe generation of a wave front with simultaneous ventriculardepolarization and QRS narrowing either in patients with normal QRS orin those with conduction disorders.

This is obtained by the formation of a virtual electrode which generatesa stimulation field significantly higher than the one in a traditionalelectrode for the physiological stimulation. Said higher current fieldallows to compromise more distant areas than the pacemaker place evenovercoming conduction disorders,—electrical bypass (EB)—. The use ofsaid virtual electrode assures an energy saving with regards to thenecessary high output and makes the placing in the septum easieravoiding difficult electrophysiological mapping procedures.

For a better comprehension of the present invention, a septalventricular stimulation system with high performance in the electric andprobably contractile synchrony, is described. This system is intended tosignificantly modify the definitive pacemaker implantation, making itmore physiological. Patients with QRS narrowing were tested, as well aspatients with AV atrio-ventricular and interventricular conductiondisturbances, showing in all of them the QRS narrowing phenomena and theorientation of the depolarization with vectors similar to those in thedepolarization through the His-Purkinje system.

EXAMPLES

The embodiments of my invention are shown in the application oftraditional pacemakers made in 50 consecutive patients who werestimulated in right septum with standard bipolar catheters. They wereused for the record of the His bundle activity and with the pacingtechnique of my invention, pacemakers, method of application and aspecial high penetration technique of system EB.

In order to use a conventional voltage a pulse generator driven by atraditional over-stimulation pacemaker was used, with programmingoutputs from 1 to 36 volts and two types of waves, a sequential biphasicand another superimposed biphasic wave, with pulse widths programmablefrom 0.1 to 2 milliseconds. The second wave uses each electrodeindividually with reference to an indifferent one with opposedpolarities. This allows the use of a traditional output and generating avirtual electrode of great magnitude of current which is the objectiveof EB stimulation (Electrical Bypass), and reducing the use of highenergy with the results previously tested.

In order to know the behavior of the left ventricle in normal patientsand with several branch conduction disturbances, a multipolar catheterthrough the coronary sinus was used. The distal dipole represents theside basal portions of the left ventricle, as it was recently shown byCARTO® search.

Forty-nine patients were successively analyzed at the EP Lab during theprocedures to evaluate sinus function and A-V conduction.

These patients were divided in two groups:

Group A (31 patients) was tested with pacing on edge of RV and in septumwith high ouput (20 volt).

Group B (18 patients) was tested with the pacing stimulation of myinvention, with the EB alternative electric pathway in septum.

In both groups the duration of the QRS was measured, both the basal aswell as during the different types of stimulation. In order to test theactivation in basal and distal portions of the left ventricle, the gapbetween the beginning of the QRS and the depolarization in the coronarysinus of the most distant portion of the left ventricle was measured.

Table 1 describes the results in relation to features and magnitude ofthe width of the QRS obtained in each case.

R- EB- SVD- QRS BASAL sSEP sAPEX VI VI VI EST 1 BCRI 160 100 — — — — EB2 BCRI 220 140 — — — — EB 3 BCRI 215 154 214 154  90 169  EB 4 BCRI 14090 120 80 70 90 EB 5 BCRI 180 128 — 120  76 — EB 6 ANG 92 104 144 — — —EB 7 ANG 120 150 240 — — — EB 8 ANG 84 96 140 40 64 112  EB 9 ANG 80 88120 36 42 86 EB 10 ANG 72 88 120 40 68 92 EB 11 ANG 78 82 144 58 58 100 EB 12 BCRD 150 150 — — — — EB 13 HBAI 90 100 150 — — — EB BCRD+ 14 HBAI146 120 165 — — — EB 15 BCRD 120 110 150 — — — EB 16 ANG 60 70 — — — —EB BCRD+ 17 HBAI 120 130 190 — — — EB BCRD+ 18 HBAI 140 100 — 68 70 98EB 19 ANG 70 85 — — — — 20 mA 20 ANG 80 100 — — — — 20 mA 21 HBAI 100110 180 — — — 20 mA BCRD+ 22 HBAI 160 120 190 — — — 20 mA 23 ANG 90 100— — — — 20 mA 24 ANG 70 85 — — — — 20 mA 25 ANG 80 100 180 — — — 20 mA26 ANG 80 100 — — — — 20 mA 27 ANG 70 100 — — — — 20 mA 28 ANG 65 90 — —— — 20 mA 29 BCRD 110 140 — — — — 20 mA 30 ANG 60 70 — — — — 20 mA 31ANG 60 65 — — — — 20 mA 32 ANG 80 90 — — — — 20 mA 33 ANG 80 90 — — — —20 mA 34 ANG 50 80 110 — — — 20 mA 35 ANG 60 76 — — — — 20 mA 36 HBAI100 170 — — — — 20 mA BCRD+ 37 HABI 120 125 170 — — — 20 mA 38 HBAI 80100 170 — — — 20 mA 39 HBAI 50 100 160 — — — 20 mA 40 BCRD 64 70 — — — —20 mA 41 ANG 55 130 160 — — — 20 mA 42 ANG 60 70 — — — — 20 mA 43 ANG 90100 140 — — — 20 mA 44 BCRI 100 120 180 — — — 20 mA 45 ANG 70 110 — — —— 20 mA 46 ANG 80 95 — — — — 20 mA BCRD+ 47 HABI 120 130 180 — — — 20 mA48 ANG 85 140 — — — — 20 mA 49 ANG 70 85 — — — — 20 mA 50 ANG 120 140180 — — — 20 mA

References: measures are expressed in milliseconds; narrow ANG=QRS lowerthan 100 msec; sSEP=width of QRS in septal stimulation; sAPEX=width ofQRS with stimulation from apex of RV; R-LF=conduction time from R to arecord of RV from the coronary cavity; EB-RV=conduction time from septalstimulation EB to a record of RV from the coronary cavity;sRV-LV=conduction time from stimulation on apex of RV to a record of theLV from coronary cavity; EST=features of stimulation; 20 mA=traditionalstimulation with output of 20 mAmperes.

As described in the table above, there are no major differences betweenQRS EB and the spontaneous QRS. The average, QRS EB has 14 msec morethan the spontaneous QRS. This delay is caused by a delta wave at thebeginning of the QRS due to the septal penetration through a muscularpathway before the arrival of the stimulus to the specialized conductionsystem. Then the remaining depolarization is exactly the same as thenormal QRS configuration. Differences regarding septal stimulation werenot observed either when it was performed with higher energy (20 volts).

In the cases where RV apex was paced, a marked difference in spike-to-LVinterval versus spike-to-LV(EB) interval was observed, LV activity beingrecorded as previously explained from the distal dipole of a multipolarcatheter located in the coronary sinus. In average, the conduction timefrom the apex of RV to LV is increased by 54 msec in respect to theseptal stimulation time EB to LV. This significant shortage ofleft-ventricle to right-ventricle time is also registered because of thepresence of complete left branch block in the basal ECG, wherein the QRSsignificantly narrows (39 msec average) after EB stimulation. It is alsoaccompanied by significant narrowing of the QRS in both cases (61 msecaverage), which supposes a more effective electric re-synchronization ofthe left ventricle.

FIG. 1 shows as an example of case 1, a patient with narrow QRS. SeptalEB stimulation shows just a slight widening of the QRS (first half ofthe figure) with a conduction sequence similar to the one of the basalQRS. FIG. 1. FIG. 2 corresponds to a patient with a complete left branchblock and ventricular malfunction, the time of basal conduction from thebeginning of the QRS to the deflection corresponding to the leftventricle through the distal electrode of a multipolar catheter placedin the coronary sinus (164 msec). FIG. 3 shows the reduction of suchtime of conduction when EB is stimulated in septum (90 msec). FIG. 3.

FIG. 4 shows the same patient, the stimulation in apex of the rightventricle keeps a conduction time to the left ventricle (169 msec(similar to the basal time), when keeping the complete left branchblock. FIG. 5 shows a ECG of a patient with sinusal rhythm and completeblock of the left branch, as the septal stimulation of high penetration(EB) “normalizes” the QRS, narrowing it. A proof of the “physiological”change in the sequence of intraventricular conduction is also thepresence of the QRS narrowing, changes of the ventricularrepolarization, with negative T waves in the precordial leads, certainlysecondary to “electrotonic memory”. Stimulation on apex of the rightventricle follows a behavior similar to the presence of the completeleft branch block in the basal ECG. In this case septal EB stimulationnarrows the QRS and generates the same changes of the ventricularrepolarization (FIG. 6).

In three cases, stimulation was conducted after the radiofrequency AVnode ablation, in order to avoid the high frequency response in cases ofparoxystic atrial fibrilation. In these patients septal stimulationshowed ventricular capture, from the same place wherein ablation wasrealized, with narrow QRS despite of the proper complete AV blockobtained.

FIG. 7 shows the bypass of the ablation site and the narrow capture ofthe QRS. On the right of the record the basal rhythm is VVI pacemakermode with complete AV block post ablation of the AV node. Note thepresence of the atria dissociated from the ventricles in the “ablat”channel. At the left side, stimulation EB, from the ablation catheter inthe same place of the ablation captures the ventricles with narrow QRSand normal depolarization-repolarization.

Septal EB stimulation shows a significant narrowing of the QRS similarto the normal conduction, through the His Purkinje system. It ispossible to interpret this fact as an entrance of the wavefront to theHis bundle, due to the special features of the EB stimulation. In somecases, the QRS similarity so suggests. However, in some circumstances,particularly when the previous QRS has a delay by the presence of thebranch block, a significant narrowing is observed, similar to the oneobserved in the simultaneous stimulation of both ventricles(re-synchronization).

FIG. 8. In a patient with left bundle branch block, the fusion withextrasystoles coming from the right ventricle are expressed as asignificantly narrow QRS.

The various embodiments described above are provided by way ofillustration only and should not be construed to limit the invention.Based on the above discussion and illustrations, those skilled in theart will readily recognize that various modifications and changes may bemade without strictly following the exemplary embodiments andapplications illustrated and described herein. Such modifications andchanges do not depart from the true spirit and scope of the presentinvention.

What is claimed is:
 1. An apparatus, comprising: an electrostimulationpulse generator, configured to provide an electrostimulation signal to afirst electrode disposed in a subject heart; and a His captureverification signal generator, configured to generate an electrical Hiscapture verification signal based on information about whether theelectrostimulation signal from the first electrode evokes a responsethat bypasses a ventricular conduction abnormality of the subject heart;wherein the pulse generator provides the electrostimulation signal tothe first electrode in the subject heart as an electrostimulation signalcomprising at least partially concurrent opposite polarity signals. 2.The apparatus of claim 1, comprising the first electrode.
 3. Theapparatus of claim 2, comprising a second electrode, wherein the pulsegenerator is configured to provide a portion of the electrostimulationsignal to the second electrode when the second electrode is disposed inthe subject heart; wherein the electrostimulation signal comprises afirst monopolar pulse delivered from the first electrode with respect toa reference and a second monopolar pulse delivered from the secondelectrode with respect to the reference.
 4. The apparatus of claim 3,wherein the pulse generator is configured to provide theelectrostimulation using the first electrode being disposed in a firstseptal location in the right ventricle near a His bundle of the subjectheart, and using the second electrode being disposed in a second septallocation in the rig ventricle near the His bundle of the subject heart.5. The apparatus of claim 1, comprising a catheter including the firstelectrode located on the catheter and the catheter having a deflectablesheath, wherein the deflectable sheath includes a distal electrode thatis configured to be electrically coupled to the signal generator.
 6. Theapparatus of claim 1, comprising a control circuit, configured todetermine whether a contraction of a ventricle of the subject heartresponsive to the electrostimulation signal exhibits a desireddepolarization-repolarization pattern.
 7. The apparatus of claim 6,wherein the control circuit is configured to use the pulse generator toprovide an electrostimulation signal to a second electrode disposed inthe subject heart when the control circuit determines that thecontraction responsive to the electrostimulation signal does not exhibitthe desired depolarization-repolarization pattern.
 8. The apparatus ofclaim 1, comprising a control circuit, configured to determine whether acontraction of a ventricle of the subject heart responsive to theelectrostimulation signal exhibits a narrow QRS width.
 9. The apparatusof claim 8, wherein the control circuit is configured to use the pulsegenerator to provide an electrostimulation signal to a second electrodedisposed in the subject heart when the control circuit determines thatthe contraction responsive to the electrostimulation signal does notexhibit the narrow QRS width.
 10. An apparatus for treating aventricular conduction abnormality of a subject heart, comprising: firstand second electrodes configured to he disposed in the subject heart, atleast one of the first and second electrodes being configured to besecured to a septal location of the subject heart; a pulse generator,configured to provide an electrostimulation signal to the first andsecond electrodes; and a His capture verification signal generator,configured to generate an electrical His capture verification signalbased on information about whether the electrostimulation signal fromthe first and second electrodes evokes a response that bypasses theventricular conduction abnormality of the subject heart; wherein thepulse generator is configured to provide the electrostimulation signalto the first and second electrodes as respective electrostimulationsignal pulses having at least partially concurrent opposite polarity.11. The apparatus of claim 10, comprising the first and secondelectrodes configured to be disposed in a septal region of the subjectheart.
 12. The apparatus of claim 11, wherein the pulse generator isconfigured to provide the electrostimulation signal comprisingelectrostimulation pulses comprising a first monopolar pulse to beprovided to the first electrode with respect to an electrical referenceand a second monopolar pulse to be provided to the second electrode withrespect to the electrical reference.
 13. The apparatus of claim 10,wherein the His capture verification signal generator is configured togenerate the electrical His capture verification signal to indicate adelay between a beginning of a QRS complex and an activation of the leftventricle free wall at a point distal from the apex of the leftventricle.
 14. The apparatus of claim 10, comprising a removable guidesheath that comprises the first and second electrodes.
 15. The apparatusof claim 14, wherein the removable guide sheath is deflectable to guidethe first and second electrodes to a target pacing region in the subjectheart at or near the septal wall.
 16. The apparatus of claim 10, whereinthe His capture verification signal generator is configured to generatethe electrical His capture verification signal based on informationabout whether the electrostimulation signal from the first and secondelectrodes evokes a response that bypasses a bundle branch block.
 17. Anapparatus, comprising: first and second electrodes disposed in a subjectventricle at or near the septal wall of a subject heart; a pulsegenerator, configured to provide an electrostimulation signal to thefirst and second electrodes; a His capture verification signalgenerator, configured to generate an electrical His capture verificationsignal based on information, received using a third electrode, aboutwhether the electrostimulation signal evokes a response indicating aconduction abnormality of the subject heart is bypassed; wherein thepulse generator provides the electrostimulation signal to the first andsecond electrodes as respective electrostimulation signal pulses thatare at least partially concurrent and of opposite polarity.
 18. Theapparatus of claim 17, wherein the pulse generator provides theelectrostimulation signal pulses as a first monopolar pulse deliveredfrom the first electrode with respect to a reference and a secondmonopolar pulse delivered from the second electrode with respect to thereference.
 19. The apparatus of claim 17, wherein the His captureverification signal generator is configured to include, in theelectrical His capture verification signal, information about whether asubject bundle branch block is bypassed.
 20. The apparatus of claim 17,comprising the third electrode, wherein the third electrode is disposedon a sheath that is removable from a catheter, and the catheter includesthe first and second electrodes.